That primary rival is United Launch Alliance, a company that the aerospace industry titans Boeing and Lockheed Martin formed in 2005.

ULA’s largest rocket, the Delta IV Heavy, costs $US350 million a launch, according to CEO Tory Bruno. It’s far more expensive that SpaceX’s $US90 million Falcon Heavy, in part because it isn’t reusable.

ULA plans to retire that launcher after about seven more missions, but the company is developing a reusable rocket, dubbed Vulcan, to compete with innovative companies like Musk’s SpaceX and Jeff Bezos’ Blue Origin.

“Vulcan will first fly in mid-2020,” Bruno told Business Insider. He added that the rocket would “start at sub-$US100 million” – a 70% discount compared with the company’s Delta IV Heavy, and a competitive price with SpaceX’s Falcon Heavy.

“We’ve each made market forecasts, and if we’re right, our solution will be economically advantageous,” Bruno told CBS News in March. “If I’m wrong and they’re right, then theirs will.”

Here’s what Vulcan could be capable of, why one ULA engineer described its recovery system as “genius,” and how the rocket may earn its keep in an increasingly crowded, challenging industry.

This story was updated with new information. It was originally published on February 24, 2018.

Delta IV Heavy used to be the world’s most powerful operational rocket. It can send nearly 32 tons of payload into low-Earth orbit — more than the weight of two standard school buses.

Using six strap-on boosters, Vulcan could lift 40 tons (nearly three school buses) into low-Earth orbit.

“Vulcan is modular, so you can add solid rocket boosters to kick up its size,” Bruno said.

That’s less than SpaceX’s Falcon Heavy, which can lift more than 70 tons (nearly five school buses) for one-fourth the price. But Bruno said there were big differences between the two systems that would make Vulcan competitive.

The key difference is the rocket’s upper stage. Falcon Heavy uses a rocket-grade RP-1 kerosene as fuel, but it can freeze in space after a few hours. Vulcan’s upper stage will use cryogenic oxygen and hydrogen, which are more resilient in the punishing temperatures of space.

ULA is also evolving its upper-stage system into what it calls the Advanced Cryogenic Evolved Stage, or ACES. After deploying a spacecraft, ACES can be left in orbit for months or years and be refueled instead of being discarded as “dead flying hulks in space,” Bruno said.

“That makes it practical to refuel them in space and use them for other purposes, or simply use them as a shuttle to run down and grab a spacecraft that you might be so heavy you could only get it to [low-Earth orbit], and then take it literally anywhere else in the solar system,” Bruno added. “That is going to completely change how we go to space and what we do there.”

“It’s not just saving a little bit of money off the launch-service cost,” Bruno said. “This could become a transportation system that enables economic activity between here and the moon and between the asteroids.”

Vulcan will also lower ULA’s launch costs by having detachable first-stage booster engines attached to a system called SMART: Sensible, Modular, Autonomous Return Technology. “We would recover about two-thirds the cost of that first-stage booster every single time we fly with no performance hit,” Bruno said.

This is different than SpaceX’s boosters, which return in one piece and conserve fuel to rocket to a landing. But payloads are sometimes too heavy and need every last drop of propellant to reach their destination in space — so some boosters inevitably get discarded despite being reusable.

“How might you perhaps not save the entire value of the booster, but get to save [most of] it every single time?” Bruno said. “The most expensive thing on the booster is the rocket engine. In fact, two-thirds of the cost of a booster is just that one part.”

Once the Smart engine package detaches, it will inflate an aeroshell to help orient it for a high-speed reentry. The shell will also insulate the engines from the intense heat generated by ploughing through Earth’s atmosphere at thousands of miles an hour.

A slender parachute will then float Smart toward the ground. But it will get some help. Using a technique pioneered in the 1960s, it will be snagged from above by a large helicopter.

“When I first heard about it, it seemed like a very strange, almost laughable concept – until you actually start to look into the history of mid-flight capture and realise that it’s actually a very genius way to do it, to reuse and capture the engines without exposing them to any sort of harsh environments like saltwater,” Jeremy Braunagel, a project engineer at ULA who works on Vulcan, said in a video.

ACES should be ready to debut in 2023 or 2024, Bruno said, with Smart following sometime after that.

United Launch AllianceA timeline of how ULA plans to transition its Atlas rocket system into the reusable Vulcan rocket system.

Though small satellites are getting smaller, big satellites always seem to get bigger and need to go farther in space. ULA is banking primarily on those big satellites for its Vulcan business.

“We’ve never seen a time when the customer has asked for less lift – that’s kind of why we took this strategy,” Bruno said, adding that flying the entire booster back could become increasingly difficult.

According to Bruno, Delta IV Heavy will retire in “the early 2020s” after launching once or twice a year. That leaves a huge opening for Falcon Heavy, especially since Musk has said SpaceX is working on a cryogenic upper stage, which may compete with ACES.

Musk has said he’d eat his hat “with a side of mustard” if Vulcan “flies a national security spacecraft before 2023.”

SpaceX is also pouring an increasingly large share of its resources into developing a 348-foot-tall interplanetary launch system called the Big Falcon Rocket, or BFR.

Meanwhile, Jeff Bezos’ aerospace company, Blue Origin, is quietly developing and building a huge, reusable rocket system called New Glenn.

The future of rockets is looking increasingly exciting, innovative, and crowded. It remains to be seen whether ULA and Blue Origin can keep up with the breakneck pace of SpaceX or carve a niche in what is indisputably a new space race.

Blue OriginThe New Glenn rocket system is expected to be a reusable, vertical-landing booster that can deliver 3.85 million pounds of thrust — about half the power of NASA’s Saturn V moon rockets.